|Topic Review (Newest First)|
|06-06-2011 01:49 PM|
ccriders Maybe I wasn't clear enough in my explanation, but look at it this way; You have a triangle consisting of a straight vertical side (the mast) with a fixed length, a Hypotenuse (Headstay, Mainstay, Jibstay, luff of Jib) with a fixed length; therefore if I lengthen the horizontal length by moving my tack forward, my angle of the mast to deck (vert. to horiz.) decreases and the top of my mast therefore will move slightly forward, no matter what my pre-bend is or will be. Do understand that this procedure is only possible if you slacken/loosen you backstay.
Tropicat nailed on the "mast".
My "fix" to reduce the weatherhelm I encountered by over a 100% cost me niltch, I'm still sailing with my old sails running a good 6.5 knts in 15 mph wind at 40 degree to the wind without wetting the rail.
I'm happy. The next owner can buy new sails that are "flat", install an hydraulic Boom-Vang and install 1 to 6 ratio out-haul and Cunningham.
|06-06-2011 07:10 AM|
I've been following this thread with interest as I went through the same gyrations several years ago. People responding are correct in that sail shape definitely plays a role in your boat's handling. However, when it comes to weather helm, your reading was correct in that where the tip of the mast is positioned has the greatest affect on weather helm. This is the very first mast adjustment in anyone's rig tuning guide.
Weather helm - tighten forestay
Lee Helm - loosen forestay
I sail with a balanced helm and a surprisingly straight mast. In 15 knots of wind I sail right up to 35 degrees apparent, while maintaining boat speed and this with a 175 genny on my furler.
Oh yeah... I sail a catamaran.
|06-04-2011 05:43 PM|
I'm not understanding what you did. How did moving the tack of the jib forward (attachment point of the furler) change the angle of the mast? Seems to me that mast angle (not pre-bend) would only change with adjustment to the jib and aft stays. I would love to see pictures of your setup showing the jib stay and the roller/furler attachments. Also comparison of the sails pulling in the same manner as the pics you previously provided which seems to indicate the luff of both main and jib to be a little soft.
I was able to improve my weather helm problems with a new sail (mine was much baggier than yours) but still have pretty strong weather helm in heavier gusts, which I have always considered a necessary evil. If I could tune them down a little I would be much happier.
|06-04-2011 02:18 PM|
|Ajax_MD||Great news, EJO. It sounds like the PO put that link in there for some reason. I'm sure the boat will be much more enjoyable to sail now.|
|06-03-2011 07:03 PM|
|EJO||Thanks for the compliment XPatriot, she does look remarkable for rolling and tipping going from white (see avatar) to blue.|
|06-03-2011 06:57 PM|
Boat looks beautiful!!!!!!!!!!
Glad it's now sailing as good as it looks. You'll have to start weight training to keep those biceps taught
|06-03-2011 02:45 PM|
Okay guys/gals I finished (see pic) the boat and sailed her twice since she got wet. I flattened the sail to no avail (still had weather-helm although less) I opted for my original thought of leaning the mast forward and increased my 'J' dimension by approx. 2" (+1.3%) by moving my furler connection a little forward and leaving the forestay (mainstay) the same length resulting in a <1.5 degree deduction in the mast to deck angle and therefore leaning the mast more forward than what it was. This resulted in an almost balanced rudder at 45 degree to apparent wind and being able to steer the boat from the tiller with one finger instead of two hands in a 20 knt wind last weekend.
Problem solved she is sailing without tiring the skipper and/or autopliot.
|05-10-2011 12:02 PM|
Yeah, draft is pretty far aft in that photo of your main. Well, try the least intrusive things first- Flattening the sail. If that doesn't work, then remove the link.
The sail doesn't look blown-out to me, but I'm not a sailmaker.
|05-10-2011 11:48 AM|
Bubblehead you hit it on the head with "previous owner(s) altered your mast to be leaning too far back by adding length to the forestay with those links" hence my comment that I wanted to take the snap shackle out from under the furler.
these are the only picks I have showing the sail up. note the weatherhelm at 15kts in the 3 pic. That's what keeps my biceps in shape but not the belly.
|05-10-2011 09:44 AM|
My boat is 46 years old and except for turnbuckles, my rig is not adjustable. I'm in the same position you are.
You say you have a non-original "rollerfurling system that has 3 extra links on the bottom of the main-stay". When you say main-stay, are you referring to the forestay that your jib flys from? If so, I suppose it's possible that a previous owner altered your mast to be leaning too far back by adding length to the forestay with those links. Removing a link may help.
At any rate, to induce pre-bend in a rig like ours, you need to tighten the lower shrouds a bit (equally). Don't go all Mongo on them, they aren't supposed to be bar-taut. This will help shape the luff.
When you sight up the mast, you should see the top 1/3 of the mast slightly curl aft.
When you get sailing, try posting some photos of your sail and trim. That will tell us a lot. Shoot from under the boom, looking up.
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